Not sure how they could broadcast at night, there are no lights on the track. All you would see is some headlights and tail lights on and off. The daytime portions I guess would work but that's only half the race lol.

Does anyone know if these races are broadcast in the US? If so, what network? I would love to be able to watch these races regularly!

I don't think they are broadcasted in the states. I think it was shown on "Sport1" (formerly EuroSport channel) over here in Germany. There is coverage at night too! Every few hours though, not non stop for 24hrs. Just as is the race coverage for the 24hrs of LeMans in three weeks will be.